Hand-mouth coordination is a critical adaptive skill, important for self-calming, object exploration and self-feeding during infancy and beyond. The developmental origins of the ability to transport objects to the mouth are not well understood, however. In the present project, this issue is addressed by considering how objects begin to function as extensions of the hand and become incorporated into the hand-mouth transport system. Behavioral and motion tracking technology will be used for this general goal; infants from 2 to 15 months of age will be studied. Three primary issues are addressed. In the first set of studies, the ability of young infants to transport their hands and a hand-held object to the mouth will be contrasted in an effort to understand how objects begin to function as extensions of the hand. In the second set of studies, infants in the middle of the first year will be studied to examine how they begin to orient objects and bring a specific part or feature of an object to the mouth. In the last set of studies, the ability of infants late in the first year to use handles as extensions of objects when bringing objects to the mouth will be considered, in part to understand the early development of tool use. Collectively, the results of the project will offer a more complete developmental picture of how later emerging adaptive behaviors involving hand-mouth transport build from younger infants' efforts to bring objects to the mouth, yield new information about how basic adaptive skills like self-feeding and tool use develop, and illuminate how these skills may be fostered in young children. PUBLIC HEALTH RELEVANCE: Hand-to -mouth transport is a critical adaptive skill for infants and adults alike, enabling individuals to feed themselves. Early problems in this skill can compromise daily living. The present project develops new methods and measures to assess hand-to-mouth transport in infants across the first year and will offer insights into how to promote this skill in young children.